Refine
Document Type
- Monograph/Edited Volume (7)
- Article (5)
- Postprint (1)
Is part of the Bibliography
- yes (13)
Keywords
- PLFA (2)
- algae (2)
- bacteria (2)
- light (2)
- microbial interactions (2)
- streambed structure (2)
- terrestrial carbon (2)
- 13C stable isotopes (1)
- C-13 stable isotopes (1)
In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photoheterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a C-13-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems.
In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photo-heterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a 13C-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems.
Wie Gesellschaften Wohlfahrt organisieren und institutionalisieren, drückt ihre grundlegenden Wertvorstellungen über gutes Zusammenleben aus.
Der Vergleich von Gesellschaften lässt sich besonders fruchtbar mit dem Konzept der Wohlfahrtsregime durchführen, das die Logiken der Produktion und Verteilung von Wohlfahrt ins Zentrum stellt und mit dem Regimebegriff die zeitliche Entwicklung durch Regierungsphasen mit einer bestimmten politischen Ausrichtung thematisiert. Deshalb werden aufgrund einer Auseinandersetzung mit der sozialphilosophischen Diskussion acht Performanzkriterien entwickelt, die als Maßstab für den Vergleich von 28 Ländern und fünf Wohlfahrtsregimen verwendet werden: Wohlstand und Wachstum; ökologische Nachhaltigkeit; Innovation; soziale Sicherung durch Unterstützungsleistungen im Risikofall sowie vorsorgend durch Bildungsinvestitionen; Anerkennung der Besonderheiten (Frauenfreundlichkeit und Migrantenfreundlichkeit); Gleichheit der Teilhabe; soziale Integration; Autonomie („freedom of choice and capabilities”).
Anschließend wird der Umbau der Wohlfahrtsregime anlässlich der aktuellen Herausforderungen und Randbedingungen für die verschiedenen Wohlfahrtsregime diskutiert. Schließlich wird untersucht, welche Gruppen in welchen Ländern welche der sechs Wohlfahrtskonzepte unterstützen, die sich bei der Faktorenanalyse von internationalen Einstellungssurveys ergeben.
Inhalt: 1. Einleitung 2. Zur Korrelation zwischen Bildungsniveau und sozialer Herkunft 2.1. Die mikrosoziologische Perspektive 2.2. Die Ungleichheit familiärer Lebenswelten 2.3. Bildungskarrieren als Ergebnisse rationaler Entscheidungen 3. Daten und Operationalisierung 4. Soziale Chancengleichheit im Kompetenzerwerb – der Ländervergleich 5. Strukturmerkmale von Bildungssystemen und soziale Chancengleichheit 5.1. Die makrosoziologische Perspektive 5.2. Institutionelle Diskriminierung 5.3. Soziale Entmischung 5.4. Private und kostenpflichtige Schulangebote 6. Erklärungsmodelle zur länderspezifischen Reproduktion sozialer Ungleichheit 6.1. Modellbildung und Modellhypothesen 6.2. Ergebnisse der pfadanalytischen Erklärungsmodelle 6.3. Diskussion der Ergebnisse 7. Strukturtypen von Bildungssystemen und die soziale Chancengleichheit 7.1. Bildungsstrukturtypen 7.2. Die Strukturtypen und ihre "idealen" Vertreter 7.2.1. Finnland (Strukturtyp: reine Einheitsschule) 7.2.2. Großbritannien (Strukturtyp: Einheitsschule und Privatschulen) 7.2.3. Frankreich (Strukturtyp: Späte Differenzierung) 7.2.4. Österreich (Strukturtyp: Frühe Differenzierung nach Leistung) 7.2.5. Deutschland (Strukturtyp: Frühe Differenzierung mit Elterneinfluss) 7.3. Strukturtypen und die Reproduktion sozialer Ungleichheit 8. Bildungsstrukturen als Ausdruck gesellschaftlicher Wohlfahrtsvorstellungen 9. Zusammenfassung